As one of the properties of pressure sensitive adhesive sheets, peelability is required in some cases, for example, in applications such as surface protection films, masking tapes for coating or for decoration, and peelable notes.
When such pressure sensitive adhesive sheets are stuck to adherends, adhesion by which the pressure sensitive adhesive sheets do not peel from the adherends is required during transport, during storage, during processing, and the like. On the other hand, it is required that the pressure sensitive adhesive sheets can be easily peeled and removed after they complete serving their function.
As pressure sensitive adhesives used in such pressure sensitive adhesive sheets, pressure sensitive adhesives whose adhesion decreases by applying a voltage are known.
For example, Patent Literature 1 discloses an electrochemically debondable adhesive comprising a high load-resistant bonding polymer having high mechanical strength and comprising an electrolyte.
In addition, Patent Literature 2 discloses an electropeeling composition comprising an ionic liquid as a pressure sensitive adhesive peelable during voltage application. Patent Literature 2 states that the ionic liquid is a molten salt that is a liquid at room temperature, has no vapor pressure, and has properties such as high heat resistance, nonflammability, and high chemical stability.